The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Feb. 15, 2011

Filed:

May. 23, 2008
Applicants:

Erik P. Eriksen, Calgary, CA;

Michael E. Moffitt, Houston, TX (US);

Tommy M. Warren, Coweta, OK (US);

Inventors:

Erik P. Eriksen, Calgary, CA;

Michael E. Moffitt, Houston, TX (US);

Tommy M. Warren, Coweta, OK (US);

Assignee:

Tesco Corporation, Houston, TX (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E21B 7/00 (2006.01);
U.S. Cl.
CPC ...
Abstract

A bottom hole assembly in a casing-while-drilling operation is retrieved by reducing the density of the fluid in the casing string above the bottom hole assembly, creating an upward force on the bottom hole assembly. As the bottom hole assembly moves upward in the casing string, fluid is pumped into the upper end of the annulus and displaced fluid flows out of the upper end of the casing string. The flow rate of the fluid flowing into the upper end of the annulus and the flow rate of the displaced fluid flowing out of the casing string are monitored and compared.


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